A semiconductor chip consists of an array of devices whose contacts are interconnected by patterns of metal wiring. For instance, in VLSI chips, the metal patterns are multiayered and are separated by layers of an insulating material which is characterized generally by a low dielectric constant. Interlayer contacts between metal wiring patterns are made by through-holes which are etched through the layers of the insulating material. In a typical chip design, there are or more wiring layers. Low dielectric constant insulating materials are employed between the wires in the same level and also between the various wiring levels.
In a typical VLSI chip, the insulating material is silicon dioxide that has a dielectric constant of between about 3.9 and about 4.1. As the speed of the chip is affected by the RC value of the insulator, enhanced speed performance requires reduction of the capacitance (C). The quest for higher integration in the chip results in the shrinkage of the dimension and tends to increase the capacitance values, unless the dielectric constant of the insulator is significantly reduced. Furthermore, with the increasing use of large scale integration in the chip design, back end wiring densities are increasing. As the wiring density increases, the need for lower dielectric constant insulating materials, i.e. interlayer dielectric (ILD) materials arises in order to improve the performance of the VLSI and ULSI devices.
Different materials that have low dielectric constants have been investigated as potential replacement materials for silicon dioxide. For instance, among the candidate materials for the ILD, fluorinated carbon polymers appear to have the lowest dielectric constant values, i.e., &lt;3. However, most of the materials with significantly lower dielectric constants such as those of fluoropolymers are thermally unstable at chip processing temperatures above 350.degree. C., thus making them unsuitable for integration in modem semiconductor fabrication technology. A thermal endurance at processing temperatures higher than 400.degree. C. after the deposition of the BEOL dielectric is frequently required in such technology.
It is therefore an object of the present invention to provide a low dielectric constant insulating material for use as a dielectric insulating layer in electronic devices that does not have the drawbacks and shortcomings of the prior art dielectric materials.
It is another object of the present invention to provide a low dielectric constant material for use as a dielectric insulating layer in electronic devices that is thermally stable at semiconductor processing temperatures.
It is a further object of the present invention to provide a low dielectric constant insulating material for use as a dielectric insulating layer in semiconductor devices that is thermally stable in non-oxidizing environment at temperatures up to 400.degree. C.
It is another further object of the present invention to provide a low dielectric constant insulating material for use as a dielectric insulating material in both interlayer applications and intralayer applications in a semiconductor device that is thermally stable in non-oxidizing environment.
It is still another object of the present invention to provide a low dielectric constant insulating material for use as a dielectric insulating layer in semiconductor devices that has a dielectric constant of less than 3.0.
It is another further object of the present invention to provide a low dielectric constant for spacing apart one or more levels of conductors in a semiconductor device.
It is still another farther object of the present invention to provide a low dielectric constant amorphous fluorinated carbon material for use as a dielectric insulating layer in semiconductor devices that can be formed from a fluorinated cyclic hydrocarbon precursor.
It is yet another further object of the present invention to provide a low dielectric constant amorphous fluorinated carbon material for use as a dielectric insulating layer in semiconductor devices that can be formed from a fluorinated cyclic hydrocarbon precursor such as hexafluorobenzene, 1,2-diethynyltetrafluorobenzene or 1,4-bis(trifluoromethyl) benzene.
It is yet another further object of the present invention to provide a low dielectric constant amorphous fluorinated carbon material for use as a dielectric insulating layer in VLSI or ULSI devices that can be deposited by a radiation or beam assisted deposition technique.